engine RPM's

Discussion in 'Mechanic and Repair' started by milo, Apr 16, 2006.

  1. milo

    milo LawnSite Bronze Member
    Posts: 1,259

    what should be the rpm's on my scag tiger cub with a 19hp kawasaki on it? they are at 3740rpm what just running and when blades are on they go to 3555rpm.. my dealer said that was perfect but my engine manual says no more than 3600rpm. also the dealer asked how my cut was and i said it cuts awesome and he said the idle is right and not to lower it... is he right???
     
  2. 6'7 330

    6'7 330 LawnSite Bronze Member
    Posts: 1,823

    3750 with the blades engaged, under no load.Every V-TWIN kawi we have is set at that speed.Now the old flathead Kawi's would be a different story.The Exmarks, and Toro's came from the factory at that setting.Actually the Toro's were closer to 3770.
     
  3. CuttinUP

    CuttinUP LawnSite Senior Member
    Posts: 337

    With the blades engaged, that is a load. I have the 17 Kaw on a walk behind and the manuel says 3600 with no load and the dealer technician said that you shoulden't go any more then 3650, 3670 max under no load on my TTHP. But I know that riders are set higher at 3750 max with no load.
     
  4. 6'7 330

    6'7 330 LawnSite Bronze Member
    Posts: 1,823

    Under no load means,the mower is sitting still, and not mowing grass with the blades spinning.Without the blades spinning, the Toro's came from the factory at over 3800.
     
  5. TURF DOCTOR

    TURF DOCTOR LawnSite Silver Member
    Posts: 2,138

    Not a problem we ran vanguards in the mid to late 90's ripping em at over 4k rpm's with 2000 + hours,but vanguards was in another post,my 2 cents we do it with clean oil all the time.
     
  6. CuttinUP

    CuttinUP LawnSite Senior Member
    Posts: 337

    Not trying to argue with you but "No load" means no load. With the blades engaged there is a load on the engine. No load is the same as free reeving an engine. When you engage the blades the rpm's drop, this is due to a LOAD being present. The Manuel says for my TTHP 3600 RPM (No Load). The manufacturer would not mean this by the way you are thinking because they can not control what blades you have(heavier blades= more load=less RPM) and other variables that they can not control. Think about it! Your Toros may come set at 3800 but they have also designed everything else(hydro pumps,blade tip speed) around this RPM.

    milo, your tech is going to be correct on this, not to say that you can't tweak it up a little.
     
  7. milo

    milo LawnSite Bronze Member
    Posts: 1,259

    hi no i do not want to make any higher. i just wanted to make sure it was ok like it is or if i should turn idle down. i will keep where it is.
     
  8. TURF DOCTOR

    TURF DOCTOR LawnSite Silver Member
    Posts: 2,138

    Most engines stay like 3600 rpm.
     
  9. 6'7 330

    6'7 330 LawnSite Bronze Member
    Posts: 1,823

    Kawi's are rated at 3800 rpm's.Put it like this-when adjusting the rpm's, the blades should be spinning.Every V-Twin kawi we have, on all brands is set at 3750, with blades spinning.We have set the V-Twins at this setting, since Kawi introduced the V-Twin's,and they all have accumulated thousands of hours . Every Kohler twin is set at 3800, with the blade's spinning.
     
  10. MJLsLawnCareNmoreLLC

    MJLsLawnCareNmoreLLC LawnSite Senior Member
    Posts: 841

    My understanding is that most kawi engines are supposed to be set at a max rpm of 3600. That is under no other load besides just running.

    Bill, I dont know if it is just coincidence that just about every kawi was set at 3750 from the factory or what. It could be that exmark or whatever mower manufacturer you use sets it up from their factory to run at 3600 rpms with the blades on so they might set the idle rpms up higher. Maybe your dealer set them higher as part of the pre-delivery setup.

    Not positive on this, but how do you know kawi even checks to make sure the engine runs at 3600 rpms and dont just bolt them up to run close to 3600 rpms and leaves it up to the buyer, whether mower manufacturer or home owner to set the rpms to the proper level?
     

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